The long term objective of the proposed research is concerned with the structure and organization of spatial memory. Major emphasis is placed on developing more detailed understanding of how spatial information is encoded and retained, and how remembered information is retrieved and used to guide behavior. This objective will be approached through the detailed study of Clark's nutcrackers. These birds harvest and store thousands of pine seeds that will be eaten months later. Detailed laboratory studies have demonstrated that spatial memory is used to find these seeds. The memory abilities of these birds will be studied with several different experimental procedures, including radial-maze-analogs, operant matching-to-sample and list learning. In addition, the abilities of some closely related species will also be studied in order to begin to evaluate the relation between memory and evolution. By studying memory in this species, and some closely related species, it is expected that considerable general information about spatial memory will result.